Heat the olive oil in a large skillet over medium heat. Add the onion and cook until soft. Add the garlic and the chicken and cook unit browned. Stir in the salt, cayenne, and Balsamic. Continue cooking until chicken is cooked through.

Cut the bell peppers in half and remove the core and seeds. Fill the peppers with the chicken mixture and lay in a baking dish. Add a few tablespoons water to the bottom of the dish and cover tightly with foil. Bake for 35 minutes.

Remove the cover and top each bell pepper half with a half slice of provolone. Put back in the oven uncovered, and bake until cheese is browned and bubbly, 5-10 more minutes.